<!doctype html>
<html>

<head>
  <title>My home page</title>
</head>

<body>
  <div>
    <h1>My home page</h1>
    <p id='para'>Hello, I am Marijn and this is my home page.</p>
    <p>I also wrote a book! Read it
      <a href="http://eloquentjavascript.net">here</a>.</p>
  </div>
  <script>
    var divStyle = document.querySelector('div').style;

    divStyle.backgroundColor = 'red';
    divStyle.border = '1px solid black';
    //divStyle.width = '100px';
    //divStyle.height = '100px';
    divStyle.backgroundColor // red
    divStyle.border // 1px solid black
    divStyle.height // 100px
    divStyle.width // 100px
  </script>
</body>

</html>